Such a sealing arrangement is described in FR 266 79 47 A1. The encoder in this case is an impulse ring which is formed integrally with the dirt deflector made of sheet metal. The encoder is located axially outside the outer bearing ring and radially opposite a sensor. The encoder has hardly any protection, if any at all, against contamination, this making it very possible for malfunctioning of the sensor unit to occur in the event of heavy contamination.